Steam treatment



Filed Oct. 16, 1929 Fig] INVENTOR ATTOREY Patented Feb. 7, 1933 "UNITED STATES PATENT oF lcE CHARLES E. LUGKE, OF NEW YORK, N. Y., ASSIGNOR TO THE BABCOOK & WILOOX COM- PANY, OE BAYONNE, NEW JERSEY, A CORPORATION OF NEW-JERSEY STEAM TREATMENT I Application filed October 16, 1929. Serial No. 899,908.

This invention relates to steam treatment,

a method of and apparatus for condition ing steam, of such character, that the degree of moisturein the steam can be accurately controlled, or entirely eliminated, or. any desired degree of superheat be imparted to the steam. employed, may mean the conversion of wet steam to less wet, of wet steam to dry, the conversion of wet or'dry steam to superheated steam, \O1 anincrease in the degree of superheat. f When moisture carrying scale forming impurities, is evaporated by the application of heat to the outside of a vessel containing steam having such moisture in suspension, those particles of moisture in contact with the confining wall 'depositthe impurities upon the surface of the wall at the time of vaporization, with the result that a heat insulating layer of scale is formed on the inher surface'of the confining wall. This layer of scale interferes with the absorption of heat by the water or steam with the result that the confining wall burns away.

A further object of this invention is to provide'a method and apparatus for drying saturated steam in such a way as to prevent the formation -of scale upon a confining wall. f These and other objects which will be apparent to those skilled in this particular art are'accom'plished by means of the invention illustrated in the accompanying drawing, inwhich Fig. 1 is a diagrammatic View, of a portion of a boiler furnace, provided with a steam conditioning device constructed in accordance with one embodiment ofthis invention; and Figs. 2 and 3 are transverse sectional views of a certain detail of construction showing different modifications thereof.

Although the present invention is shown in connection with a fuel fired steam generating'boiler, for the purpose of condition- The term conditioning, as herein lar steam source, and might be employed, for example, inplace of a reheater.

"This'invention contemplates the conditioning of a body ofsteam by introducing a heating or drying fluid to the interior of the body of steam, in such a way as to secure a thorough mixing action. This conditioning fluid, which in the illustrative embodiment is superheated steam but may, obviously, be other Inediums, delivers the steam conditioning heat to the body in such a way that any moisture, as when the steam being conditioned is saturated, is vaporized in suspension, so that any scale forming impurities remain in the body of steam as suspended dust and do not adhere to the confining wall.

The particular embodiment of the present.

invention which has been chosen for the purposes of illustration, includes a devicefor,

eliminating. all moisture from saturated steam duringits travel from a steam and water drumto the superheater, with the'result. thatonly dry steam entersthe latter. The dryingof the body ofsaturated steam is accomplished by applying the vaporizing heat to, the, body internally and awayfrom the confining surface. In this Way, vaporization of water carrying scale formingimpurities in. contact with the walls of the superheater.

is avoided, so that no scaleis deposited upon suchwalls. i

As illustrated, the present invention is shown in connection with aboiler furnace 1, havingany desired form of steam generating boiler 2 associated therewith. A connection .is provided for conveying saturated steam from the steamspace of a steam and water drum 4, to the inlet header 5 of a superheater 6, which is illustrated in the form of a plurality. of bent tubes connecting the, inlet header with the outlet header17. A connec-, tion 8 is provided for carrying the superheated steam to the pipe line 9, which in .turn

conveys it toany desired point ofconsumption. v

' This invention is particularly applicable to such an arrangement for the purpose of preventing the deposition of scale in the superheater tubes, @by eliminating all scale bearing moisture fromth'e body of js aturated r to its introduction thereto.

steam flowing to the superheater and prior This is accomplished by introducing the conditioning fluid to the interior of the stream of saturated steam in such a way as to obtain a thorough mixing of the two fluids.

In the illustrated arrangement, where the conditioning fluid is superheated steam, a pipe. connection 10 leads from the superheated. steam outlet connection 8, to the inlet of the steam circulator, such as a compressor or blower 11, which is employed to overcome the drop in pressure of steam flowing through the superheater and to establish the desired pressure in the pipe connection. A steam circulator outlet is connected by a line 12 with the saturated steam line 3 at a point between the steam and water drum 4 and 1 the superheater inlet header 5, for the purpose of delivering a regulatable amount of superheated steam to the interior of the body of saturated steam flowing to the superheater. The amount of superheated steam used for this purpose is so controlled as to obtain the desired conditioning effect upon the saturated steam so that the latter is either converted from wet steam to dry, or has a certain degree of superheat imparted to it. Preferably, a certain amount of superheat is imparted by the conditioning device. When this is done, the amount of superheated steam recirculated by the steam circulator 11, and hence the amount of steam conditioning heat delivered to the saturated steam, is controlled by the degree of superheat in the steam entering the superheater header 5.

As illustrated, this is accomplished by means of a thermostat 13, inserted in theline 8,near the header 5 and connectedto a thermostatically operated valve located in the line 10 such as is well known in the art and which may be of any desired construction. It will be apparent that operation of the valve 14 in accordance with the temperature of the steam entering the superheater, wil1 control the amount of steam delivered to the circulator 11, andby it returned to the saturated steam line 3.

It will also be apparent that, assuming substantially constant pressure conditions in the steam and water drum 4, any change in the condition of the steam entering the superheater tubes willresult in a corresponding and proportional change in the condition of the steam at the superheater outlet. In this way, the illustrated embodiment of the present invention provides a simple and automatic control of steam conditions at the superheater outlet. Similarly, when the thermostat 13 has been set, in consideration of a definite pressure of saturated steam, any change in the latter must be. compensated for by. a proper readjustment of thermostat. The particular form of mechanism emi,eee,isi

ployed for injecting the superheated steani into the line 3 may be of any desired construction. As illustrated in Fig. 2, a standard form of Venturi tube is inserted in the line 3 and the return pipe 12 terminates in a nozzle 16 for delivering the superheated steam at the mouth of the venturi.

As illustrated in Fig. 3 an annular form of venturi is used. The pipe connection 12 terminates in a nozzle 17 surrounded by a conical block 18, and delivering the conditioning fluid to the space between the block and a centrally positioned cone 19 in the line 3 for reducing the friction of flow and at the same time obtaining a thorough mixing action. The Venturi tubes permit obtaining a high velocity flow, resulting in a zone of'turbulence at the point where the conditioning fluid is introduced, and a return to high pressure without an. over all, loss of pressure. This turbulence causes the desired thorough molecular mixing of the fluids. At the same time, the Venturi throat has a tendency to cause any particles of moisture flowing along the wall of line 3 to be sprayed off and embodied in the flowing stream so as to be subjected to the conditioning action.

It will be apparent that the present inven tion provides a simple buteflective arrangement for conditioning a body of steam so as to produce a desired degree of wetness or a desired degree of superheat at will.

Although I have described a particular mode of operation, as carried out by a specific form of apparatus, it will be apparent that. various changes, additions, omissions, and substitutions may be made therein without departing from the spirit of this inventionor the scope of the appended claims.

What I claim is new and desire to secure by Letters Patent is:

1. The combination with a steam, boiler having a steam and water drum and a superheater connected to said drum of means for delivering a portion of the steam fromthe said su erheater to the stream of saturated steam owing from said drum to said superheater, and means for controlling the operation of said first named means in accordance with the degree of superheat.

2. The combination with a steam boiler having a steam and water drum and a superheater connected to said drum, of an outlet for superheated steam from said superheater, a connection for returning superheated steam fromisaid superheater-to the saturated steam flowing to said superheater from said drum, a circulator in said connection, a valve for controlling the amount of steam flowing through said connection and means for opening and closin said valve in connection with variations in t e temperature of steam entering said superheater.

3. In.apparatus of the class described,.a steam superheater, a steam inlet line conducting steam to the superheater, an outlet 7 line conducting steam fromthe superheater, a by-pass line conducting superheated steam from the outlet line to the inlet line whereby the superheated steam mingles with the steam entering the superheater, a ump in the bypass line for boosting the ow in that line, and a valve in the by-pass line for controlling the weight of superheated steam pass- 10 ing to the inlet line, sald byass line returna ing only a part of the super eated steam to flow again through the superheater while superheated steam is flowing through the outlet line to a point of use.

p CHARLES E. LUCKE. 

